Where does “chelidonius” come from?

chelidonius (Latin) comes from Ancient Greek χελιδόνιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “chelidonius”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	χελιδόνιος	of, belonging to, built by, like, or pertaining...
2	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
3	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

Every word from Proto-Indo-European -yós →

chelidonius — Etymology, Origin & Word History | Etymology Explorer